I am asking for opinions, although I think I know what the problem is. I was out testing a new engine the other day, and it was working great. Good temperature, good oil temperature, pressure at about 80 hot.  I was starting to push the rpm up to full power, and at 5100 the oil pressure suddenly dropped to 20. I brought the speed back to idle, and the oil pressure recovered.  I did a couple more laps, and the oil pressure stayed at 80, but not going to full power.  I think it is pumping the sump dry at high engine speed. Anyone else encountered this?  The oil pan I have is a Moroso that is supposed to be good at controlling windage.  It only holds 7 quarts though.  I have a feeling I am going to have to modify the pan to hold a lot more, like maybe 10-14 quarts. I am hoping that will be the fix, otherwise, the only other alternative is to go with a dry sump. The engine is a 540 and will turn a well-loaded A3 Aggressor at 5600. I did cut the filter open and take the element out for inspection, and there was nothing significant in it so I know that there was no damage, but I cannot run up to full power until I have this issue resolved.

And 80 psi at what rpm?.

The pickup clearance is around 3/16". That is pretty much the recommended distance. The oil pressure I run is around 80 throughout the operating range. The oil pump relief valve is shimmed to provide that pressure from idle to wide open.  The only variance is a slightly lower pressure at idle. This is not an engine that is used for drag racing, but something that has to run continuously at high rpm. Drag racing, this situation would never happen.

There's your problem.

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Is this a marathon boat?

GT

Does your oil pump bypass to the pan or to the suction side of the gears?  If into the pan, does it discharge away from the pickup?

Just curious what kind of oil pressure gauge do you have I had this issue with my 454 and found out that my electric oil pressure gauge was going bad


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x2! !! I was there for that..and that carried over to my bunghole puckerin on your 502... all good now tho..

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The oil pressure will always drop as the oil temperature goes up. When the oil gets really hot, 260-280 the hot running pressure will be around 65.  There are folks who claim 260-280 is too high. It's not. G.M. actually used to say up to 300 is okay (measured in the pan). The oil can take it, so can the bearings, no problem. For that reason, I set up my oil pumps to make very high initial oil pressure. I always run an oil cooler, it needs it. After running sustained 4500+ everything gets pretty warm. All the clearances have to be right, really good parts used or it will grenade.

After doing an absolutely Ludacris amount of research I have learned that 220° to 250°F is ideal and where we always target as a control.

65# at temp is perfect IMHO.

The problem I think we have here is a turbulent oil sump.

I run the oil cooler off of the water dump to have the ability to warm the oil up and once running hard keeps the oil right around perfect for as long as there's gas in the tank.

GT

It is too bad that one cannot see exactly what is going on inside the oil pan when things are happening. The oil pan I chose was based on some research I did. This particular design was recommended by Reher Morrison as having excellent windage control. As for my cooling system, my set up is pretty much identical to yours, and I agree, it works well and also the oil is warmed up more quickly.

Just a stupid question.

Have you tried running the pan 1 quart high?

Honestly adding a quart of Lucas stabilizer couldn't hurt a Damn thing IMHO (running 1 quart high).

It should only be about 1/2" difference in overall level.

Just a thought.

GT